Early 273 intake problems

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I would modify that intake so quick it would have already been on there and running. Ten times.
 
pishta said:
That is indeed a 64-65 intake. Put some hardened washers on it and call it a day. I ran a Performer on the 65 heads with washers and it never leaked. AS for the holes that dont line up, take all the bolts out and manually line up the intake again. I bet they all line up with 5/16 bolts. I got to question the wrench needed to tighten those '5/16' bolts. If its a 9/16 hex then they are 3/8 bolts. 5/16 take a 1/2 wrench as those head angles are 3/8 for sure. Whats head casting number?

2465315 – 1964-1965, 273 LA-series small-block, 1.78/1.50 valves

2532080 – 1964-1965, 273 LA-series small-block, 1.78/1.50 valves

My pic of a real deal 65 intake and 64 heads, note skinny 5/16 bolt face angles and casting line on head that follows bolt angle. 66+ heads are at a 90 to the intake face. Check your head(s)for this line, buck says they don't have 'em.
View attachment 1715424281
View attachment 1715424285
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They are 5/16 bolts. The wrench is a 1/2. I just went checked the casting #. They are 2465315’s I’ll get pics tomorrow. No locating pins
 
grimreaper said:
2465315 are definitely 273 heads. Time to ream bolt holes for fit.
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Who knows how many times that manifold has been tried and never installed. Could be mis boxed or mis drilled. It looks NOS. There's often a reason why it's still around and has never been used.
 
toolmanmike said:
Who knows how many times that manifold has been tried and never installed. Could be mis boxed or mis drilled. It looks NOS. There's often a reason why it's still around and has never been used.
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Agree...the bolt holes look to be for the '66 - later ('920) heads and just put in an early box.
 
Jedrattle, shoot a pic of the front of the head where I took my bolt angle pic. Those sure sound like 64-65 heads but the bolt angle is all 66. you can still make them work. just use the 5/16 bolts and hardened washers, you can open the holes a little with a bit. If I had not made my sheet metal intake for my 5/16 '65 heads, I'd trade you straight up for those later bolt angle heads. Alot easier to fab an intake flange with flat bolt faces.
 
The new aluminum intake has an angular raised boss shown in post 1 - picture 1 - holes #4 and #6.

You may have later model heads. OR if your heads have the older casting numbers, they could have been machined to the new specifications [manifold bolt holes being square to the intake surface]. These were the early years for the LA motors, and who knows what happened to your car in the last 55 years. If Chrysler had ordered say 10,000 heads with the old casting number and had a bunch leftover, would they trash them or machine them to the newer specs? And give them the new part number.
 
The "315" heads are 64-65. They have a small, closed combustion chamber so they give higher compression and are desirable in that respect. The '64-'65, 4 barrel intake manifolds were cast iron, early design single plane and are heavy and hard to find.
The '66 and later heads have larger combustion chambers but intake manifolds are easy to find and there are several designs and brands to choose from. To me, the "Offy" intake manifold mounting holes look like later model size and angle, despite what the box says.
So, you have started collecting parts to give you options to go different directions. Now, you need to decide what you want to build next to suite your style of driving.
 
Richard Sweet said:
The "315" heads are 64-65. They have a small, closed combustion chamber so they give higher compression and are desirable in that respect. The '64-'65, 4 barrel intake manifolds were cast iron, early design single plane and are heavy and hard to find.
The '66 and later heads have larger combustion chambers but intake manifolds are easy to find and there are several designs and brands to choose from. To me, the "Offy" intake manifold mounting holes look like later model size and angle, despite what the box says.
So, you have started collecting parts to give you options to go different directions. Now, you need to decide what you want to build next to suite your style of driving.
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Note, no 4 barrel in 64. The 66 and 67 closed chambers were the same as the 64 and 65 heads.
 
Richard Sweet said:
The "315" heads are 64-65. They have a small, closed combustion chamber so they give higher compression and are desirable in that respect. The '64-'65, 4 barrel intake manifolds were cast iron, early design single plane and are heavy and hard to find.
The '66 and later heads have larger combustion chambers but intake manifolds are easy to find and there are several designs and brands to choose from. To me, the "Offy" intake manifold mounting holes look like later model size and angle, despite what the box says.
So, you have started collecting parts to give you options to go different directions. Now, you need to decide what you want to build next to suite your style of driving.
Click to expand...
To be precise, '64-'65 (#315) heads, and, '66 (#178) heads are small chamber, 5/16" attaching bolts with the weird angle...'67 (#920) heads are small chamber, 3/8" bolts with conventional angle. The '68-'69 (#675) heads had the large chambers and non-adjustable, hydraulic rocker arms. These heads (#675) also cont'd on through '74 on 318's.
 
65Val said:
To be precise, '64-'65 (#315) heads, and, '66 (#178) heads are small chamber, 5/16" attaching bolts with the weird angle...'67 (#920) heads are small chamber, 3/8" bolts with conventional angle. The '68-'69 (#675) heads had the large chambers and non-adjustable, hydraulic rocker arms. These heads (#675) also cont'd on through '74 on 318's.
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#315 64-65
#080 64-65
#178 66 Early
#234 66 Late
#920 66 4 barrel with CAP
#951 66 D Dart
#920 67 273/318
#675 68-69 273 open chamber and 68-71 318
All the heads are closed chamber until the #675 head in 1968
There were 3 different part numbers for the #920 heads.
 
Richard Sweet said:
Jed,
Remember that just changing to a 4 barrel intake and carb. will not make much difference in power. The crank, cam, lifters, pistons, rods, heads & ports & combustion chambers and distributor timing may all need to be changed if you want better performance.

The 273 engines had forged cranks and solid lifters but the 2 barrel engine components were different than the 4 barrel engine components. Also, rebuilding a 273 may cost more than switching to a 318, 340 or 360 engine.

Sorry if you are probably already hooked as a hot-rodder, join the club.
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Yes, the 2 barrel cams were a bit smaller and of course the 4 barrels had more compression, a slightly bigger cam, a dual point distributor and a 4 barrel carb and intake.
 
Basic 273 cam specs:

1965 180 hp 2 barrel .395 /.405 lift 240°/ 240° duration
1965 235 hp 4 barrel .415 /.425 lift 248°/ 248° duration
1966 235 hp 4 barrel .420 /.430 lift 248°/ 248° duration
 
Richard Sweet said:
Jed,
Remember that just changing to a 4 barrel intake and carb. will not make much difference in power. The crank, cam, lifters, pistons, rods, heads & ports & combustion chambers and distributor timing may all need to be changed if you want better performance.
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Have to disagree on this. Changing from the terrible 2bbl intake system to 4bbl AFB makes a world of difference, even if you change nothing else.
 
All 64 to 67 273's, 2 barrel or 4 barrel, had forged cranks, forged rods, solid cams, and cast pistons. Even 2 barrel engines had 8.8 :1 compression and pistons .02" from the top of block. They respond very well to 4 barrel intakes and carbs, even if you do nothing else. Wiggle that intake and see if you can't get everything to line up. And do not use those sorry steel shim intake gaskets.
 
66fs said:
All 64 to 67 273's, 2 barrel or 4 barrel, had forged cranks, forged rods, solid cams, and cast pistons. Even 2 barrel engines had 8.8 :1 compression and pistons .02" from the top of block. They respond very well to 4 barrel intakes and carbs, even if you do nothing else. Wiggle that intake and see if you can't get everything to line up. And do not use those sorry steel shim intake gaskets.
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Half century ago, I put a 340 intake on a 65 273 using homemade tapered washers. Worked just fine.
 
From post #1. It still looks like the intake manifold [5/16] bolt bosses are at a different angle than the head intake surface. They are parallel on later models. I'd say it is packaged correctly.
 
The bolt holes on the 66 and newer heads are at 90° to the intake surface. You may be right. (On my phone. Picture is small)
 
pt70 said:
From post #1. It still looks like the intake manifold [5/16] bolt bosses are at a different angle than the head intake surface. They are parallel on later models. I'd say it is packaged correctly.
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The bolt head in that pic is definitely NOT parallel to the manifold flange.
 
Jed,
I'd still advise looking for a 2 barrel carb rated at 500cfm, which is what you'd use with a 4 barrel. I don't have a specific reference but they are available. Remember that most 318's and many 360 engines also had 2 barrels stock. Also, 2 barrels are easier to rebuild, but I'd look for a new one that is tunable. It might be just as expensive as a 4 barrel however.
There are also other things that you can easily do to your engine to help: dual exhaust, blocking off the exhaust heat riser into the intake manifold, going to electric or mechanical choke, and making sure that the distributor is set and timed right and of course correct valve settings (very important with solid lifters).
What problems did you have with your 2 barrel carbs?
 
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